The Spoon helps, too, if you have that to throw. If not, usually before I go to the Moon, I find the most powerful weapon I can get and buy a crapload of 'em. That'll usually do about 6000 or more when thrown.

And I don't know how many people know this, but one of Edge's last weapons (either the Murasame or the Masamune--I think it's the Masamune, but I'm not sure) will cast Haste on you if you use it. I always make this his first move. Just go to Items and press up, like you would if you were equipping him, select it, and the hand will point to Edge if it's the right weapon. Don't worry, the weapon is still there and you can do that as much as you want.

Another good tip is to cast Bersk on Cecil, then on Edge when he runs out of things to throw.